tj3006
.375 Atomic
Posts: 2,058
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Post by tj3006 on Oct 20, 2022 5:14:16 GMT -5
Looking at the Various Sources of reloading data, And the huge difference in stated velocity, I would think a worthy experiment, To take a Blackhawk, with rather large Cylinder gap, chrony a few loads, the adjust the gap and fire a few more ? It might be a bigger job , than I realize, and I know velocity, has other variables, But that would be an interesting read !...tj
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Post by bobwright on Oct 20, 2022 8:11:55 GMT -5
I no longer have a chronograph, but when I did I tested loads in both a Ruger and a Smith & Wesson. Also tested loads in Rugers with 4 5/9" and 7 1/2" barrels, and Smiths in 4" and 6" barrels.
My findings were eye-openers and I just accepted published velocities as sort of "approximate velocities." After years of loading and shooting, plus studying, I set aside the charts and books and just loaded and shot what felt right. (Or felt Wright?)
Bob Wright
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jgt
.327 Meteor
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Posts: 801
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Post by jgt on Oct 20, 2022 8:44:18 GMT -5
Most of the time I see cylinder/barrel gap talked about, it is in the concept of accuracy. I have always accepted there will be less velocity with a larger gap, but I do not accept the notion a tighter cylinder gap has anything to do with accuracy. Mainly because some of my most accurate guns have a larger than custom cylinder gap. Another issue I have with tight cylinder gaps are how little shooting it takes to make the gun hard to use without stopping to clean. The amount of velocity loss to me is perfectly within acceptable perimeters for me to have a firearm that does not have to be babied to keep it operational.
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Post by handgunhuntingafield on Oct 20, 2022 9:22:12 GMT -5
Gap aside. From one barrel to another of the same length you will see vast differences in velocity. There are all kinds of scientific reasons.
Loading manuals stated velocity just relates to the firearm or universal action used. It’s just a ballpark for what your velocity might be.
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Post by bradshaw on Oct 20, 2022 9:25:04 GMT -5
Most of the time I see cylinder/barrel gap talked about, it is in the concept of accuracy. I have always accepted there will be less velocity with a larger gap, but I do not accept the notion a tighter cylinder gap has anything to do with accuracy. Mainly because some of my most accurate guns have a larger than custom cylinder gap. Another issue I have with tight cylinder gaps are how little shooting it takes to make the gun hard to use without stopping to clean. The amount of velocity loss to me is perfectly within acceptable perimeters for me to have a firearm that does not have to be babied to keep it operational. ***** James.... one fine summer = day, on the sidehill behind the houses of Bill Ruger senior & junior, I squeezed off 400 rounds of Remington experimental .357 Maximum ammo from one of the seven prototype SRM revolvers. It was all aimed fire, yet squeezed off bon rapide. Cylinder gap measured .001 to .0015-inch. The revolver grew too hot to hold with bare hands, yet did not bind up. Binding can become a problem with ammunition which readily fouls, or when chamber LEADES and/or EXIT HOLES (throats) are rough, poor chamber-to-bore alignment, rough or off-axis forcing cone, or when the cylinder face is not square to barrel... et cetera. Roughness in chamber leade and exit hole invites bullet abrasion. Chamber-to-bore runout can shaves lead or jacket material. tj.... you’re free to experiment. Easiest way, fetch into a Dan Wesson, use feeler gauges to set the barrel at whichever gaps you choose, choreographing each step. Preferably with more than one load. To kill two birds with one stone, target for accuracy @ 25 yards, minimum. 50 yards is better. Record all data, including temperature and light conditions (relevant to accuracy). Then, fill us in on Singleactions. My experiments with barrel/cylinder gap were done with Dan Wesson revolvers, with my focus on accuracy out to 100 meters, with some shooting @ 200 meters. I entered the experiments ready to see a tight cylinder gap killing a loose cylinder gap. I was rudely awakened. The widest gap I tested: .010-inch. Random accuracy shooting with S&W M-29’s of exception accuracy gave just about no favor I could see to a .003” gap over a .010” gap. In comparing various .44’s, Ruger Super Blackhawk and M-29, a lousy forcing cone instantly doomed accuracy. Individual dimensions within a revolver are like individual instruments in an orchestra. Some sdimensions/instruments count more than others. And how they play together affects the music they make. David Bradshaw
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Post by Encore64 on Oct 20, 2022 9:43:49 GMT -5
Looking at the Various Sources of reloading data, And the huge difference in stated velocity, I would think a worthy experiment, To take a Blackhawk, with rather large Cylinder gap, chrony a few loads, the adjust the gap and fire a few more ? It might be a bigger job , than I realize, and I know velocity, has other variables, But that would be an interesting read !...tj Ballisticsbytheinch.com
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jd
.30 Stingray
Posts: 205
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Post by jd on Oct 20, 2022 17:26:47 GMT -5
I have a Ruger Super Single Six stainless 22 LR with a 4 5/8" barrel. New from the factory the cylinder gap was 0.013". The gun shot really well so I didn't want to send it back to Ruger where they would have most certainly replaced the barrel as who knows how well it would have shot with a new barrel. The large gap was rather annoying when shooting so I had Ben Forkin set the barrel back and he adjusted the cylinder gap to 0.003". I had chronographed several types of ammo before sending it back, and again with the smaller cylinder gap after getting it back. Basically, the velocity was the same for both cylinder gaps... Of course, the 22 LR is a low pressure cartridge. I don't know how it would play out with a high pressure cartridge...
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tj3006
.375 Atomic
Posts: 2,058
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Post by tj3006 on Oct 20, 2022 18:09:13 GMT -5
Thank you for all the input ! I don't have a Dan Wesson revolver, And unless we get a handle on inflation, I might not ever be able to buy a red ryder, and a tube of B Bs, anytime soon. Mostly Joking but not entirely ! I forgot about the ones with the Barrel wrench, I think what I might do, Is Shoot a couple loads out of the gun I send out next , write down the results and the gap, and shoot again when it comes back ! I have Factory flat top 44 Special, That Measures at .007, Shrink it Down to 002 and shoot again !...tj
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KRal
.375 Atomic
Posts: 1,070
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Post by KRal on Oct 20, 2022 20:34:44 GMT -5
I handed off a Ruger Mag-na-port Stalker, with a cylinder gap of .012, to Gary Reeder for a barrel setback to .002. We discussed the issue and he said there’s usually no accuracy gain by tightening the gap - only velocity gain. From his experience, every .003 over .002 of gap, you’d loose about 80 fps +or- of muzzle velocity. I found his statement to be pretty accurate.
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Post by junebug on Oct 21, 2022 11:27:56 GMT -5
So for every .001 of gap over .002 you loose more velocity than you do cutting an inch off the barrel? So should your revolver be 800 fps faster when you get it back? So in theory you could cut a barrel back from 7 1/2 to 5 1/2 and reset the cylinder gap to .002 and still wind up with a faster revolver than you started with. That would be a win win more packable and faster. This is a serious question, and not just gas on a fire.
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Post by Encore64 on Oct 21, 2022 11:34:40 GMT -5
I believe there are too many variables for any one size fits all formula.
I doubt anyone could even list all the variables that alters velocity.
I've read studies where the "experts" claim larger barrel gaps are less important using heavier (longer) bullets due to the longer duration of the gap being bridged.
Probably some merit and some BS in all information. Tomorrow's research may be different from Today's...
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KRal
.375 Atomic
Posts: 1,070
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Post by KRal on Oct 21, 2022 19:18:04 GMT -5
June bug,
I’d say, in theory and by the math, yes that would be true. But, in reality, I’d say no. I’m sure at some point in the gap Gary’s comment would know longer be valid. My .012 gap was and extreme example and I was not expecting a 800fps gain on return, but I was expecting a gain - that’s been several years ago and I can’t recall exactly what the gain was, but it was better than 200fps With my 10” barrel. I really didn’t sharp shoot Gary on the topic, just thought it was very interesting. As Encore64 stated, it’s just too many variables to to say that’s correct in all situations.
PS….I went back reading my original post and realized I had a typo - my apologies. I correct to .003. I kept trying to figure how you came up with 800fps… lol…now I know.
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Post by zeus on Oct 22, 2022 6:35:03 GMT -5
I guess I’ve never cared because we don’t shoot these revolvers for speed. We adjust charges to get the load we want. I’ve shot animals with 1900 fps 454 loads down to 800 fps 458s. The 1050-1150 fps node works incredibly well on game in pretty much all calibers with a bullet matched to that critter. In fact, the only 454 slug I’ve ever recovered was from a 90lb axis doe at 125 yards. FA 260FP at 1890 fps (Fermin loves this load!) Shot through shoulders and bullet was in offside hide. Hide was stretched bad on offside but bullet didn’t exit. Retained 70%. She spun and looked behind her before she tipped over. Speed isn’t always the answer. I can say I never changed a factory gun to correct B/C gap in the last 30 years (dang that hurts to type 😥) unless they were getting a full custom build. I wouldn’t worry so much about the gap as I did finding an accurate load. Ive never owned a ruger that wouldn’t shoot well with the right load and they aren’t hard to find that load usually. As an overthinking engineer, I do understand the desire to wonder and test but for normal stuff, my advice is that time is better spent on stuff that matters like tight groups 🤣. Having said that, I don’t remember the last time I had a chance to shoot anything handgun wise so I may have trouble hitting water if I fall out of a boat 🤷🏻♂️
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Post by Encore64 on Oct 22, 2022 6:51:24 GMT -5
This thread has put a emphasis on why forums are important...
We all get to post what we find important and what works for us as individuals.
For me, this is far more educational than reading a written article by a single source. While that's OK too, multiple inputs work better.
These learning points have been a mainstay in my customs.
While many post about expensive grips, cch colors, pivot pin and screw colors, etc...I try to focus on lockup, alignment, throat size, barrel gap, forcing cone, etc.
No such things as right and wrong, just different.
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KRal
.375 Atomic
Posts: 1,070
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Post by KRal on Oct 22, 2022 7:02:29 GMT -5
I can second Glenn’s statement on not setting back the barrels on factory guns - I got that .012 gap Blackhawk from him 🤣🤣🤣🤣
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